An original recording of music is typically mastered for delivery to a two-channel audio system. In particular, the original recording is mastered such that the sound reproduction on a typical stereo system having two audio channels creates a specific auditory sensation. In a typical audio system, there are two audio channel sources, or speakers, and the original recording is mastered for playback in such a configuration.
It has become very popular for individuals to listen to music using ear-based monitors, such as headphones, earphones, or earbuds. Unfortunately, because the original recordings are mastered for the two audio channel sources, assuming that the listener will be observing sound by both ears from both channels, the playback of music on ear-based monitors does not provide a proper listening experience as intended by the artist. This is because the manner in which the original recording was made was intended to be observed by both of the listener's ears simultaneously. This externalization of the sound source allows the listener's brain to identify the different sound source locations on a horizontal plane, and to a lesser extent it allows the listener's brain to identify depth.
There are two key issues that are present when using ear-based monitors. Both the physical delivery of the music (or sound data stream) to the listener and the physical capabilities of the drivers delivering the sound to the listener's ears each have limitations. The limitations have prevented individuals from experiencing the best possible sound as originally constructed in the studio. Notably, when using ear-based monitors, the physical delivery to the listener's ears isolates each of the two different audio tracks into specific left and right channels. This isolation prohibits the brain from processing the sound information in the manner in which it was originally mastered. This results in the internalization of the sound, which places the perception of all the sound information directly between the listener's ears.